Left-handed snails, giant wombats, spiny trilobites, zombie ants, glyptodonts…these are a few of the fascinating animals and plants whose fossils spring to life across the pages of A History of Life in 100 Fossils, a new offering from Smithsonian Books.

Selected from the collections of the Smithsonian’s National Museum of Natural History in Washington, D.C., and the Natural History Museum in London, each fossil is beautifully photographed and explored in-depth with a captivating description of its importance to the story of evolution and life on Earth. Organized chronologically from the Precambrian through the Paleozoic, Mesozoic and Cenozoic eras, the book reveals the remarkable and persistent unfolding of fantastic life forms across the Earth as revealed in the fossil record.

Co-authors Aaron O’Dea of the Smithsonian Tropical Research Institute in Panama and Paul Taylor of the Natural History Museum in London carefully compiled the images in this book from hundreds of possibilities.

One of the first and oldest entries, a 3.5 billion-year-old rusty red stromatolite fossil, is arguably the most important. Dominating the world’s oceans for a staggering 3 billion years, stromatolites eventually filled the atmosphere with enough oxygen to enable the rise of complex oxygen-breathing organisms.

Aaron O’Dea

The oddest entry is a spiral bezoar (fossilized feces) recovered from ancient sea sediments and which once was imbedded in the intestine of a prehistoric shark.

Most touching: The Laetoli footprints from Tanzania, left in a matter of seconds some 3.5 million years ago, appear to show the path of a small family of early hominins, Australopithecus afarensis, wandering through a volcano’s devastation.

Steller’s sea cow wins as the saddest entry, “a sad tale of a once magnificent beast driven to extinction by hunting,” O’Dea, a paleobiologist, says. “Without its fossil record we would have had no idea that the animal was naturally widely abundant until a few thousand years of hunting whittled them away to almost nothing.”

Other fossils examined include Cambrian worms from China that provide a window on early animal life in the sea, ancient insects encapsulated in amber, the first fossil bird Archaeopteryx and the last ancestor of humankind.

Writing A History of Life in 100 Fossils with Taylor “was a fantastic experience,” O’Dea observes in his blog. “Researching in detail about fossil groups I had previously paid little attention to, spinning evolutionary tales with a single slab of rock and crafting them in a way that could be accessible to all. As I wrote I tried to weave all the big biological themes into the book; natural selection, convergent evolution, sexual selection, extinction, the origin of life and even parasitism.”

AHistory of Life in 100 Fossils is brimming with epic tales of survival and migration, evolution and destruction once concealed in the buried remains of animals and plants that lived long ago.

]]>http://smithsonianscience.org/2014/10/new-book/feed/0When will a volcano explode, ooze or lie silent?http://smithsonianscience.org/2014/09/will-volcano-explode-ooze-lay-silent/
http://smithsonianscience.org/2014/09/will-volcano-explode-ooze-lay-silent/#commentsMon, 29 Sep 2014 19:00:34 +0000http://smithsonianscience.org/?p=32547Volcanoes are a source of fascination for many, attracting a steady stream of visitors worldwide. While the danger of sudden eruptions may add to the […]

Volcanoes are a source of fascination for many, attracting a steady stream of visitors worldwide. While the danger of sudden eruptions may add to the thrill, it is a genuine risk for tourists and nearby residents. But how can one know if a sleeping volcano is about to explode?

Forecasting volcanic eruptions has been thrown into the spotlight with the weekend tragedy on Japan’s Mount Ontake, where more than 30 hikers are presumed dead after an eruption of toxic fumes and ash. Smithsonian Science asks research geologist emeritus and volcano expert Richard Fiske, from the Smithsonian’s National Museum of Natural History, about the science of predicting explosions.

How do you predict a volcanic eruption?

Fiske: You can’t predict the exact time when a volcano might erupt, but you can anticipate volcanic activity. There are two main ways scientists can detect potential volcanic activity using special instruments:

The first is an increase in small earthquakes in the region below a volcano. These earthquakes signal the movement of magma, which is lava or molten rock underground, within the volcano. Small earthquakes, undetectable to most people, occur below the surface of the volcano as the magma rises, breaking rocks within the volcano.

The second signal that scientists can detect is the inflation of the volcano. Many volcanoes inflate like a balloon before they erupt. The ground surface actually puffs up. This can’t be seen with the naked eye, but with the right ground instruments and satellite imagery, scientists can detect this change in the ground.

Pu’u O’o Crater Lava pond, Hawaii (Photo by Greg Bishop)

Is it possible that a volcano can erupt with no previous signs?

Fiske: If a volcano is monitored instrumentally, it is very unlikely that any major eruption could occur without any previous earthquakes or inflation being recorded. But there is one type of volcanic eruption that can be near impossible for scientists to anticipate.

More minor eruptions can occur when groundwater gains access to the hot magma in the volcano, generating large amounts of steam. This steam can build up pressure and create a minor “phreatic” eruption, an outburst of steam, ash and rock unaccompanied by lava. This build up of steam can be constantly happening in the background, making it difficult for scientists to discern when such a minor eruption is imminent. This is what seems to have happened on Japan’s Mount Ontake over the past weekend.

Mount Ontake, Japan. (Photo by Atsushi Ueda)

Are there other types of volcanic eruptions?

Fiske: The different types of eruptions taking place at volcanoes are largely controlled by the nature and volume of the lava. If the lava is sticky, then the gases build up in it and it tends to explode. In lava that is more fluid-like, like those found in volcanoes in Hawaii, most of the gases just bubble out of it and don’t cause explosions. In these kinds of eruptions, the lava just flows out of the volcano, almost like syrup, into the surrounding landscape.

There are many volcanoes in Japan. Why is that?

Fiske: Japan is a place where the tectonic plates of the Earth are converging and one plate is descending beneath the other plate. As that plate descends it stimulates melting of the Earth’s crust and the resulting magma rises up to form a volcano. This process is called subduction.

This situation is also found in the United States, where volcanoes have formed in Alaska, Washington, Oregon and northern California. The volcanoes found in Japan and the U.S. belong to a group of volcanoes called the Ring of Fire. This group contains 452 volcanoes that are located in a ring around the Pacific Ocean. This group includes more than 75 percent of the world’s active and dormant volcanoes. Most of these volcanoes erupt sticky lava, which contains gases that can explode with great force. That is why volcanoes in the Ring of Fire, including the volcanoes in Japan, are known to be very dangerous.

]]>http://smithsonianscience.org/2014/09/will-volcano-explode-ooze-lay-silent/feed/0New: myVolcano crowd-sourcing apphttp://smithsonianscience.org/2014/09/new-myvolcano-crowd-sourcing-app/
http://smithsonianscience.org/2014/09/new-myvolcano-crowd-sourcing-app/#commentsTue, 02 Sep 2014 15:06:31 +0000http://smithsonianscience.org/?p=32173myVolcano is a crowd-sourcing app that enables you to share your photographs and descriptions of volcanic hazards, as well as collecting samples and measurements of […]

myVolcano is a crowd-sourcing app that enables you to share your photographs and descriptions of volcanic hazards, as well as collecting samples and measurements of volcanic ash fall, helping scientists to gather vital new information about volcanic eruptions. myVolcano has been made possible through collaboration with the British Geological Survey and the Smithsonian Institution’s Global Volcanism Program. Click hereto learn more.

]]>http://smithsonianscience.org/2014/09/new-myvolcano-crowd-sourcing-app/feed/0Cutting through the dust: Radar shows moon’s true face for first timehttp://smithsonianscience.org/2014/08/cutting-dust-radar-shows-moons-true-face-first-time/
http://smithsonianscience.org/2014/08/cutting-dust-radar-shows-moons-true-face-first-time/#commentsTue, 26 Aug 2014 18:07:57 +0000http://smithsonianscience.org/?p=32128We’ve seen a serious series of super moons this summer and the show’s not over yet. Mark your calendars: the next one will light up […]

We’ve seen a serious series of super moons this summer and the show’s not over yet. Mark your calendars: the next one will light up on Tuesday, Sept. 9.

While it may seem sunny and clear up on a super moon, a steady rain of space dust and particles is zipping in and striking the moon day in and day out. Undetectable from Earth, these tiny travelers are moving fast.

“Most particles hit the ground at several kilometers per second or more,” explains Bruce Campbell, a geologist at the Smithsonian’s National Air and Space Museum. “A particle of dust moving at that speed will break a pretty good chunk off a rock.” This particle rain is the dominant erosive effect on the moon, part of an endless process of the rocks being broken down and the dust gradually building up.

This radar image reveals how the lunar impact crater known as Aristillus looks beneath its cover of dust. The radar echoes reveal geologic features of the large debris field created by the force of the impact. The dark “halo” surrounding the crater is due to pulverized debris beyond the rugged, radar-bright rim deposits. The image also shows traces of lava-like features produced when lunar rock melted from the heat of the impact. The crater is approximately 34 miles in diameter and 2 miles deep. Click to enlarge. (Credit: Bruce Campbell, Smithsonian’s National Air and Space Museum; Arecibo/NAIC; NRAO/AUI/NSF)

So what you see when you look at the moon is dust,15- to 60-feet-deep in places, built up over 4 billion years.

Recently, however, Campbell and his colleagues have figured out a way to peek through that dust layer. Two new radar images published recently in the Journal of Geophysical Research show the moon’s true face, and it’s not a pretty picture. The moon’s pockmarked surface tells a violent tale of thousands of meteor and asteroid explosions, ancient lava flows and the passage of billions of years of deep time. Smithsonian Science asked Campbell about these latest images.

Q: How does one take a radar picture of the moon?

Campbell: Radar signals are beamed from a transmitter at the Arecibo Observatory in Puerto Rico, strike the moon, bounce back and are caught by receivers at the National Radio Astronomy Observatory in Green Bank, W.Va. We use radar with a long 70-centimeter wavelength that penetrates through the moon’s dust, sometimes reaching a hard surface below. By measuring minute differences in the time it takes for the radar waves to return, and their radio frequency, we can make an accurate image of the moon’s surface. This technique has been used to study many objects in our Solar System, including asteroids and other planets.

Q: One of your new images is of the impact crater Aristillus. What does it show that can’t be seen in a telescope image?

Campbell: We can see large boulders and fragmented rocks really close to the crater that have been thrown up and flipped over. They didn’t go very far – they were just lifted out of the hole as the meteorite exploded underground. Some of this material slumps back into the hole as the crater forms. Beyond that you can see a dark “halo” of pulverized debris that’s been thrown ballistically, catapulted out and traveling great distances. The radar exaggerates these subtle compositional changes and differences in rock abundance below the dust layer. We are also able to detect lava-like melt flows formed from the heat of the impact.

This image reveals previously dust-hidden features around an area known as Mare Serenitatis, or the Sea of Serenity, which is near the Apollo 17 landing site. The radar observations were able to “see” approximately 33-50 feet below the lunar surface. The light and dark features are the result of compositional changes in the lunar dust and differences in the abundance of rocks buried within the soil. Click to enlarge. (Credit: Bruce Campbell (Smithsonian’s National Air and Space Museum; Arecibo/NAIC; NRAO/AUI/NSF)

Q: A second image shows the Mare Serenitatis (Sea of Tranquility), a feature of the moon that can be seen from earth. What did you find there?

Campbell: Mare Serenitatis was carved out of the moon some 4 billion years ago by a massive asteroid impact. We don’t see impacts like that in our solar system anymore because asteroids of this enormous scale were pretty much depleted from the inner solar system about 3.5 billion years ago. Still, the moon has several dozen large basins carved out by giant impacts like that.

One big finding from our latest image of Mare Serenitatis is a kind of ghostly outline in the middle of the crater that defines two large fields of lava that formed at different times in the moon’s history. When the Mare Serenitatis crater was formed the moon was still warm enough for magma to come close to the surface, and hundreds or thousands of lava flows emerged in the crater’s bottom and began to fill it up. The lava would flow for a period of time, stop, and then another round of eruptions would occur.Over a billion years these layers stacked up between 2 and 3 kilometers deep. The radar exaggerates the differences in the mineral composition between these lava flows and we are able to see some of the later flows quite clearly.

Q: Most of the moon’s craters are very circular in shape as if meteors and asteroids only strike its surface directly from above, and never from an angle. Why is that?

Campbell: Meteorites and asteroids are moving so fast when they hit the moon that the time it takes for one to burrow deep into the moon’s surface (as deep as two or three miles) is actually less than the time it takes for the shockwave to pass through the object and break it up. A shockwave caused by the impact reaches the back of the meteorite after the meteorite is far underground and then it explodes. The meteorite is completely fragmented in the explosion, and most of it is distributed out over the crater. So, it is almost like you detonated something underground. This is why most of the moon’s craters look so circular; only a few meteorites arrive at a large enough angle to make an oblong crater.

]]>http://smithsonianscience.org/2014/08/cutting-dust-radar-shows-moons-true-face-first-time/feed/0Human Evolution Rewritten: We owe our existence to our ancestor’s flexible response to climate changehttp://smithsonianscience.org/2014/07/human-evolution-rewritten-flexible-response-climate-change/
http://smithsonianscience.org/2014/07/human-evolution-rewritten-flexible-response-climate-change/#commentsThu, 03 Jul 2014 18:01:52 +0000http://smithsonianscience.org/?p=31201Many traits unique to humans were long thought to have originated in the genus Homo between 2.4 and 1.8 million years ago in Africa. A […]

Many traits unique to humans were long thought to have originated in the genus Homo between 2.4 and 1.8 million years ago in Africa. A large brain, long legs and the ability to craft tools along with prolonged maturation periods were all thought to have evolved together at the start of the Homo lineage as African grasslands expanded and Earth’s climate became cooler and drier. Now a paper published in Science today outlines a new theory that the traits that have allowed humans to adapt and thrive in a variety of varying climate conditions evolved in Africa in a piecemeal fashion and at separate times.

New climate and fossil evidence analyzed by a team of researchers suggests that these traits did not arise as previously thought, in a single package in response to one specific climatic trend. Rather, these defining Homo traits developed over a much wider time span in response to a much more climatically variable environment, with some traits evolving in earlier Australopithecus ancestors between 3 and 4 million years ago and others emerging in Homo significantly later. The research team includes Smithsonian paleoanthropologist Richard Potts, Susan Antón, professor of anthropology at New York University, and Leslie Aiello, president of the Wenner-Gren Foundation for Anthropological Research.

“The traits that typify our own species Homo sapiens weren’t there right at the beginning of the evolution of the Homo genus; instead, humanness evolved in much more of a mosaic pattern,” explains Potts, curator of anthropology and director of the Human Origins Program at the Smithsonian’s National Museum of Natural History.

“Climate instability we have found would have translated to major shifts in resource availability including fresh water and food. This instability favored genetic traits and behaviors that promoted the evolution of flexibility in how well early humans responded to change. This is quite different from the idea of adaptation to a particular ancestral habitat and is a very important change in our thinking” Potts added.

A large brain, long legs, the ability to craft tools and prolonged maturation periods were all thought to have evolved together at the start of the Homo lineage in response to the Earth’s changing climate; however, scientists now have evidence that these traits arose separately rather than as a single package. (Image courtesy Rick Potts, Susan Antón and Leslie Aiello)

To reach these conclusions, the team took an innovative research approach, including developing a new climate framework based on the Earth’s astronomical cycles from 2.5 million to 1.5 million years ago. This paleoclimatic data was integrated with new fossils and understandings of the genus Homo, archaeological remains and biological studies of a wide range of mammals (including humans). However, it was the recently discovered skeletons of Australopithecus sediba (~1.98 Ma) from Malapa, South Africa, that really cemented the idea for Potts that the evolution of the Homo genus involved a period of evolutionary experimentation and mixing of traits.

“A. sediba possesses a bizarre combination of features. It has a really small brain, the size of a chimpanzee’s, but also a human-like hand. It also has aspects of the face that resemble the genus Homo but has a foot that doesn’t look anything like the genus” Potts explains. “This makes sense from the standpoint of the environment at the time, where habitats were fluctuating between more wooded and more open grassland landscapes due to shifting intensity of wet and dry periods. Small populations would have become isolated at times and later merged, which would have lead to a novel evolutionary combinations of traits.”

This chart depicts hominin evolution from 3.0-1.5 million years ago and reflects the diversity of early human species and behaviors that were critical to how early Homo adapted to variable habitats, a trait that allows people today to occupy diverse habitats around the world. (Image courtesy Rick Potts, Susan Antón and Leslie Aiello)

We live today in a very unusual period where there is only one species that exists in our evolutionary tree. Multiple species of Homo are known to have lived concurrently during the earlier time of morphological experimentation. Along with the climate and fossil data, evidence from ancient stone tools, isotopes found in teeth and cut marks found on animal bones came together in this research to depict how these species may have coexisted.

“Taken together, these data suggest that species of early Homo were more flexible in their dietary choices than other species,” Aiello said. “Their flexible diet—probably containing meat—was aided by stone tool-assisted foraging that allowed our ancestors to exploit a range of resources.”

Evolutionary and historic climate studies not only shed light on how we came to be, says Potts, but also give us a broader view of current climate change problems.

“These kinds of studies show that we do live on an unstable Earth in terms of its climate, however, humans are adding totally new influences to the environment in ways perhaps more precarious than we even thought.”

“Human features were selected for adaptability, but our earlier ancestors show there have always been limits to that. Our astonishing ability to adjust to new and changing circumstances is something that I think gives us some hope for the future,” Potts says.

“The question ahead for human beings is whether we can use our capacity for technology, culture and social interaction to a sufficient extent to avoid the kinds of precarious situations even members of our own evolutionary history faced in their past,” he added.

The team concluded that the flexibility demonstrated by our ancestors to adjust to changing conditions ultimately enabled the earliest species of Homo to vary, survive and begin spreading from Africa to Eurasia 1.85 million years ago. This flexibility continues to be a hallmark of human biology today, and one that ultimately underpins the ability to occupy diverse habitats throughout the world.

Future research on new fossil and archaeological finds will need to focus on identifying specific adaptive features that originated with early Homo, which will yield a deeper understanding of human evolution.

]]>http://smithsonianscience.org/2014/07/human-evolution-rewritten-flexible-response-climate-change/feed/7Climate change to impact even deep-ocean ecosystemshttp://smithsonianscience.org/2014/06/climate-change-will-impact-even-deep-ocean-ecosystems-scientists-say/
http://smithsonianscience.org/2014/06/climate-change-will-impact-even-deep-ocean-ecosystems-scientists-say/#commentsTue, 24 Jun 2014 15:05:49 +0000http://smithsonianscience.org/?p=31080Even tiny crustaceans scuttling across the deepest, darkest depths of the ocean floor will feel the effects of climate change, according to a new study […]

Even tiny crustaceans scuttling across the deepest, darkest depths of the ocean floor will feel the effects of climate change, according to a new study published in the journal Global Ecology and Biogeography. “The deep sea is so remote and so very, very cold that we wondered if it too will be impacted by climate change,” explains Gene Hunt, a paleobiologist at the Smithsonian’s National Museum of Natural History in Washington, D.C. “Our research shows the answer is yes.”

This is a scanning electron microscope image of the shell of a deep-sea Ostracoda (Crustacea). The excellent fossil record of microscopic ostracod fossils in the deep ocean was used to estimate past biodiversity changes in a recent study by scientists based in Hong Kong, the United States and Norway. They determined that even ecosystems in the deepest ocean will feel the impact of climate change. (Image courtesy of Moriaki Yasuhara, The University of Hong Kong)

Hunt and colleagues reached their conclusion by looking closely at the well-preserved fossil record of tiny deep sea ostracods (crustaceans) that lived in the North Atlantic during the last 20,000 years. In particular they examined how communities of these crustaceans responded to previous climate change events (periods known scientifically as the Younger Dryas, which occurred 12,900-11,700 years ago, and Heinrich 1, which occurred 17,000-14,600 years ago) during which the earth’s climate became rapidly cooler. This cooling interrupted the flow of cold currents from the North Atlantic Ocean down to the ocean bottom, causing the deepest parts of the ocean to become warmer.

“As these perturbations took place ostracod diversity on the ocean bottom increased and species composition changed,” Hunt explains. “More of some kinds of species appeared in the fossil record while there were fewer of other species.”

Hunt explains that basically population compositions changed in response to changing environmental conditions. When deep cold water warms, species normally restricted to shallower or warmer waters can extend their ranges downward. These animals could either have been going up or down in depth or shifting laterally, trying to find their preferred temperature and environment.

“One unusual aspect of this study is that it focuses on time scales of decades to centuries, which strangely enough, is the hardest time period to try to nail down because it is too long for human observation but too brief to resolve in the fossil record,” Hunt continues.The strong reliability of the fossil record from the ocean floor, however, allowed the team to study changes on this time scale. In shallow waters, waves mix the sediments of different ages together. In the deep ocean this effect is much less strong and a constant rain from above of little shells from algae and other small organisms continuously forms fine sediment, which is extremely well preserved year after year. Core samples taken from these sediments were used in the study.

“Given the record of what we see occurred in the past, it is likely that changes on the same scale and magnitude will occur in the future,” the researchers conclude in their paper. “Our results imply that future climate changes may involve abrupt reorganization of marine ecosystems and global diversity patterns.” –John Barrat

]]>http://smithsonianscience.org/2014/06/climate-change-will-impact-even-deep-ocean-ecosystems-scientists-say/feed/0Smithsonian Welcomes “Nation’s T. rex” to Washington, D.C.http://smithsonianscience.org/2014/04/smithsonian-welcomes-nations-t-rex-washington-d-c/
http://smithsonianscience.org/2014/04/smithsonian-welcomes-nations-t-rex-washington-d-c/#commentsWed, 16 Apr 2014 12:03:05 +0000http://smithsonianscience.org/?p=30247On April 15 the National Museum of Natural History took delivery of a nearly complete Tyrannosaurus rex skeleton. Called the Nation’s T. rex, it will be the centerpiece of […]

On April 15 the National Museum of Natural History took delivery of a nearly complete Tyrannosaurus rex skeleton. Called the Nation’s T. rex, it will be the centerpiece of the museum’s new 31,000-square-foot dinosaur and fossil hall, which is slated to open in 2019. The current dinosaur and fossil hall will close to the public at the end of the day April 27 in preparation for the largest, most extensive exhibition renovation in the museum’s history.

To celebrate the legacy of dinosaurs in the Nation’s capital, a variety of programs will be offered for the remainder of the month of April. The museum also plans to launch three interim dinosaur-focused exhibitions this year that will give visitors a chance to immerse themselves in the ancient world of dinosaurs and cutting-edge paleontological research. The museum is planning additional exhibitions and programs for 2015–2019.

Tyrannosaurus rex Osborn (Cast) Known as the “Wankel T. rex,” the rare fossil was found in 1988 by Kathy Wankel, a rancher from Angela, Mont., on federal land near the Fort Peck Reservoir in eastern Montana.

“Tyrannosaurus rex is truly the king of dinosaurs,” said Kirk Johnson, the Sant Director of the National Museum of Natural History. “We could not be more excited to welcome the Nation’sT. rex to Washington so it can be enjoyed by our 8 million visitors a year and serve as a gateway to the vast world of scientific discovery.”

The Nation’s T. rex

The new T. rex, on loan for 50 years from the U.S. Army Corps of Engineers, was discovered on federal land in 1988 by Montana rancher Kathy Wankel. A team of paleontologists from the Museum of the Rockies in Bozeman, Mont., led by paleontologist Jack Horner, excavated the fossil from 1989 to 1990. It was then transferred to the Museum of the Rockies by the Corps for preparation and housing. It is one of the largest and most complete T. rex specimens ever discovered, with 80–85 percent of the skeleton recovered. The Nation’s T. rex arrived April 16 via FedEx.

On April 15, 2014, the National Museum of Natural History welcomes the Nation’s T. rex to the Smithsonian Institution. The Tyrannosaurus rex specimen, on loan from the U.S. Army Corps of Engineers, is the Museum’s first nearly-complete T. rex skeleton, and will be the centerpiece of the Museum’s renovated fossil hall slated to open in 2019. (From left) Kirk Johnson Ph.D., Sant Director, National Museum of Natural History, Smithsonian Institution; Kathy and Tom Wankel, the individuals who discovered the T.rex in Montana in 1988; and Lt. Gen. Thomas P. Bostick, Chief of Engineers and Commanding General, United States Army Corps of Engineers. (Photo by James Di Loreto / Smithsonian Institution)

The New Dinosaur and Fossil Hall

The new hall will be named in recognition of David H. Koch, a philanthropist and executive vice president of Koch Industries Inc. His gift—$35 million of the exhibition’s total projected cost of $48 million—is the largest single gift in the history of the Natural History Museum. The exhibition will showcase impressive specimens from the museum’s unrivaled collection of 46 million fossils; structured as a journey through time, it will start from the formation of Earth and the beginnings of life through 10 geologic time periods and two major extinctions.

As the renovation progresses, the museum will update visitors about major milestones in the immense makeover through various channels, including social media and Q?rius, the museum’s educational learning lab, and temporary exhibits around the building.

Rex Room

Dinosaurs will continue to be on view at the museum through three new interim exhibitions and additional exhibitions and programs during the five-year renovation period. The 1,830-square-foot Rex Room, opening April 15, will offer visitors the unique opportunity to see staff members unpack, catalog, photograph and 3-D scan the 66-million-year-old bones of the Nation’s T. rex. Visitors will also have the rare chance to see a line-up of skulls from four different species of tyrannosaur specimens loaned by the Bureau of Land Management.

Augmented Reality Dinosaurs

The “Augmented Reality Dinosaurs” exhibition opens in late May on the museum’s second floor. Appshaker, a London-based digital company, created a project that allows museum goers to interact “virtually” with dinosaurs such as T. rex, Triceratopsand Troodon, in a setting that represents their ancient natural habitat.

Last American Dinosaurs

“The Last American Dinosaurs: Discovering a Lost World,” a 5,400-square-foot exhibition, opens Nov. 25 and tells the story of the final days of dinosaurs found in the Hell Creek Formation of North Dakota. Visitors can explore this world of 66 million years ago, before an enormous and sudden asteroid impact drastically altered the flora and fauna forever. Triceratops, T.rex and many other fossils large and small will help visitors appreciate how the planet’s ecosystems respond to drastic environmental changes. The exhibition will also feature a special area on fossilization and fossil finding as well as the museum’s popular FossiLab, a working laboratory staffed by experts and volunteers that gives visitors a personal glimpse into fossil preparation and the day-by-day process of paleontological discovery.

]]>http://smithsonianscience.org/2014/04/smithsonian-welcomes-nations-t-rex-washington-d-c/feed/0Give us the telescopes and we’ll find the asteroid mines!http://smithsonianscience.org/2014/02/give-us-the-telescopes-and-well-find-the-asteroid-mines/
http://smithsonianscience.org/2014/02/give-us-the-telescopes-and-well-find-the-asteroid-mines/#commentsThu, 27 Feb 2014 12:47:37 +0000http://smithsonianscience.org/?p=29517An 880-pound asteroid moving at 38,000 miles per hour hit the moon last September with a blast equivalent to 15 tons of TNT. While errant […]

An 880-pound asteroid moving at 38,000 miles per hour hit the moon last September with a blast equivalent to15 tons of TNT. While errant asteroids have graced Moon and Earth with their fiery and explosive presence for millennia, for the first time humans may soon return the favor by blasting on a few asteroids.

There has been much hype recently about the possibility of new start-up private companies–including one backed by James Cameron–being able to harvest water and precious metals from asteroids flying near the Earth. Known as Near Earth Asteroids or NEAs, these asteroids have been touted as reservoirs of trillions of dollars of untapped resources ready for the taking. Are asteroids floating mines that we can use in the future to augment Earth’s depleting resources? To separate fact from science fiction on this subject Smithsonian Science writer Micaela Jemison turns to astrophysicist and asteroid mining researcher Martin Elvis of the Harvard-Smithsonian Center for Astrophysics with a few questions.

Q: First, what is an asteroid and what kinds of materials might we harvest from one?

Martin Elvis: An asteroid is a big rock floating in space. They come in all shapes and sizes, from several hundred miles across to basketball size. They also come in a lot of different compositions, from a solid lump of iron to carbonaceous material unchanged from the beginning of our solar system.

We are most interested in harvesting platinum group metals and water from asteroids. The platinum we can use on earth, but the water is only truly valuable for use in space. By harvesting water from asteroids we can have a liquid supply for astronauts and a source of rocket fuel and oxygen for astronauts to breathe once the water is separated into its elements.

This animation consists of 57 separate images captured by the Japanese Hayabusa spacecraft in 2005 as the tiny asteroid Itokawa (535 by 294 by 209 meters in size) rotated underneath it.

Q: What characteristics must an asteroid have to be considered a good candidate for mining?

Martin Elvis:An asteroid must have at least $1 billion worth of material that we want to make mining it worth the investment. Space is expensive! Finding out what asteroids are made of is tricky. We can’t take samples from the hundreds of thousands of asteroids out there. Instead we can make estimates by taking observations with telescopes.

With a telescope we can tell if an asteroid is made of solid iron, lumps of stone or carbonaceous material from space, because each material reflects a different color of light. This reflection can only give us an indication of what is on an asteroid’s surface, not of what is underneath. This information is valuable as it enables us to narrow the field to a few asteroids possibly suitable for mining. As the platinum metals we are interested in harvesting are found dissolved in iron, asteroids with large amounts of iron would be one the first ones we would investigate. Telescopes can only get you so far. The next step is to send a robotic probe to do further prospecting.

In this artist’s conception, Jupiter’s migration through the solar system has swept asteroids out of stable orbits, sending them careening into one another. (Image by David A. Aguilar)

For an asteroid to be worth testing, it first has to be easy to reach and not just in terms of how far away it is. We are doing a lot of research in identifying asteroids that are in similar orbits around the sun as the Earth, as these are the easiest asteroids to get to. We call these Near Earth Asteroids or NEAs. Once we have found some asteroids on the same path as the Earth, then distance comes into play as our rockets can go only so fast. Time is money for asteroid mining and the longer it takes the rockets to get the asteroid the more expensive it will be!

Q: Do we know where all the Near Earth Asteroids are in our solar system?

Martin Elvis:Not at all! We know where almost all the big ones are, those greater than half a mile across, but those as small as only 100 yards across, we only know a few percent. There are thousands and thousands left to be found. This is what I am trying to work on – identifying the NEAs and their orbits, as well as assessing their suitability for mining. The great thing is we don’t need to develop new technology to do this; many telescopes already have the capacity to do this work. We just need a lot more time with these telescopes and the right instruments to find out what all these asteroids are made of.

Q: How do the robotic probes identify what the Near Earth Asteroid is made of beneath the surface?

Elvis:The robotic probes need to get up and personal with the NEAs but preferably they wouldn’t touch the surface of the asteroid. A delicate spacecraft interacting with thousands of tons of space rock makes for a dangerous and complicated mission. We’d prefer to keep the probes a few hundred yards above the surface where they can assess what is underneath by measuring X-rays from the sun being reflected off the asteroid. These reflected X-rays give very clear signatures of the different elements beneath the surface. In looking for water, however, we may use a different technique – shooting a laser at the surface. As the laser creates a hole we can measure the water vapor escaping from the hole using a spectrometer. These techniques are still being developed and need work.

Q: How would we get the materials we harvest back down to earth?

Martin Elvis:After sending the probes to do the prospecting we would send out very large rockets and automated mining robots to collect the material. I think we would want to practice the mining operation locally first before setting off into space. NASA has had similar ideas and they plan to practice first by bringing back an asteroid and “parking” it somewhere in the orbit of the moon so they can experiment with mining techniques there. This practice plan could happen as early as 2020 to 2025.

This technique could also be used when trying to harvest water from NEA’s. Water can make up to 20 percent of the mass in some asteroids. One billion dollars worth of water found in suitable NEAs to be brought back to an orbit in Earth-moon space would mean moving an asteroid of 1,200 tons. That’s not much more than NASA is planning to move, and could make for a worthwhile venture.

Astronomers have theorized that long-ago asteroid impacts delivered much of the water now filling Earth’s oceans, as shown in this artist’s conception. If true, the stirring provided by migrating planets may have been essential to bringing those asteroids.

Asteroids containing enough platinum to make mining worthwhile would be too large to drag to Earth-moon space. For those asteroids the metal would have to be remotely extracted. We would just transport the refined metals required back to Earth, and only 200 tons are needed to yield $1 billion, so that could make the venture financially viable. Still, there is a lot of technology that needs to be developed.

Q: This venture would take a lot of money. If there are very few Near Earth Asteroids with the materials we want, is it worth the investment?

Martin Elvis:We don’t know for sure, but I’m bullish on NEA mining. When investing in a capitalist venture like this you are always taking a risk. Mining the first few asteroids will be the most difficult, both from a financial investment and technological standpoint. Once the first few operations start making big profits then the cost of getting into space will come down. The rockets will become more powerful and that will result in many more NEAs becoming worthwhile to mine. As with most technology the greatest cost is at the beginning of development. All we need is a few good asteroids!

]]>http://smithsonianscience.org/2014/02/give-us-the-telescopes-and-well-find-the-asteroid-mines/feed/2Wetlands sinking with human-built structureshttp://smithsonianscience.org/2013/12/burdened-with-human-built-structures-wetlands-are-sunk/
http://smithsonianscience.org/2013/12/burdened-with-human-built-structures-wetlands-are-sunk/#commentsThu, 05 Dec 2013 11:57:21 +0000http://smithsonianscience.org/?p=28939Left to themselves, coastal wetlands can adapt to sea-level rise. But humans could be sabotaging some of their best defenses, according to a review paper […]

Left to themselves, coastal wetlands can adapt to sea-level rise. But humans could be sabotaging some of their best defenses, according to a review paper from the Smithsonian Environmental Research Center and the Virginia Institute of Marine Science published Thursday, Dec. 5 in Nature.

Development along the mouth of the Elk River, a tributory of the Chesapeake Bay. (USGS photo by Jane Thomas)

The threat of disappearing coastlines has alerted many to the dangers of climate change. Wetlands in particular—with their ability to buffer coastal cities from floods and storms, and filter out pollution—offer protections that could be lost in the future. But, say co-authors Matt Kirwan and Patrick Megonigal, higher waters are not the key factor in wetland demise. Thanks to an intricate system of ecosystem feedbacks, wetlands are remarkably good at building up soil to outpace sea-level rise. But this ability has limits. The real issue, the scientists say, is that human structures such as dams and seawalls are disrupting the natural mechanisms that have allowed coastal marshes to survive rising seas since at least the end of the last ice age.

“Tidal marsh plants are amazing ecosystem engineers that can raise themselves upward if they remain healthy, and especially if there is sediment in the water,” said Megonigal of the Smithsonian Environmental Research Center. “We know there are limits to this and worry those limits are changing as people change the environment.”

Pat Megonigal studies sea-level rise at SERC’s experimental wetland in Maryland. In the mid-Atlantic, sea level is rising at a rate of roughly 3 millimeters per year. So far this marsh is building soil quickly enough to keep pace. (SERC)

“In a more natural world, we wouldn’t be worried about marshes surviving the rates of sea level rise we’re seeing today,” said Kirwan, the study’s lead author and a geologist at the Virginia Institute of Marine Science. “They would either build vertically at faster rates or else move inland to slightly higher elevations. But now we have to decide whether we’ll let them.”

Wetlands have developed several ways to build elevation to keep from drowning. Above ground, tidal flooding provides one of the biggest assists. When marshes flood during high tide, mineral sediment settles out of the water, adding new soil to the ground. It is one of the ecosystem’s most successful responses to the threat of sea-level rise. When sea-level rise accelerates and flooding occurs more often, marshes can react by building soil faster. Below ground, the growth and decay of plant roots adds organic matter—an effect that rising carbon dioxide levels seem to enhance. Even erosion can work to preserve wetlands, as sediment lost at one marsh can be deposited at another. While a particular wetland may lose ground, the total wetland area may remain unchanged.

But everything has a threshold. If a wetland becomes so flooded that vegetation dies off, the positive feedback loops are lost. Similarly, if sediment delivery to a wetland is cut off, that wetland can no longer build soil to outpace rising seas.

The impact of direct human behavior, not rising seas or higher CO2, has the most power to alter those thresholds, the scientists report. Groundwater withdrawal and artificial drainage can cause the land to sink, as is happening now in the Chesapeake Bay.

A meandering creek dissects a salt marsh in the Plum Island Estuary, Mass. Some of these marshes formed after European settlement due to sedimentation associated with deforestation. (Matt Kirwan, Virginia Institute of Marine Science

According to the article, because of this kind of subsidence, eight of the world’s largest coastal cities are experiencing relative sea-level rise greater than climate change projections. Dams and reservoirs also prevent 20 percent of the global sediment load from reaching the coast. Marshes on the Yangtze River Delta in China survived relative sea-level rise of more than 50 millimeters per year since the seventh century, until the building of more than 50,000 dams since 1950 cut off their supply of sediment and sped up erosion.

In addition to building vertically, marshes can also respond to sea-level rise by migrating landward. But, the authors note, human activities have hindered this response as well. Conventional ways of protecting coastal property, such as dykes and seawalls, keep wetlands from moving inland and create a “shoreline squeeze,” Kirwan noted. Because rates of marsh-edge erosion increase with rates of sea-level rise, the authors warn that the impacts of coastal barriers will accelerate with climate change. –Kristen Minogue

]]>http://smithsonianscience.org/2013/12/burdened-with-human-built-structures-wetlands-are-sunk/feed/1Mapping Venus with radarhttp://smithsonianscience.org/2013/11/mapping-venus-with-radar/
http://smithsonianscience.org/2013/11/mapping-venus-with-radar/#commentsMon, 18 Nov 2013 15:29:57 +0000http://smithsonianscience.org/?p=28796 The surface of Venus is hidden beneath a perpetual blanket of clouds, but radar allows scientists at the National Air and Space Museum to […]

The surface of Venus is hidden beneath a perpetual blanket of clouds, but radar allows scientists at the National Air and Space Museum to examine the rocky surface of the planet. The geologic history of the planet is being documented through analysis of regional radar maps. The lowlands of Venus are dominated by volcanic lava flows, which have many features similar to ones found on volcanoes on Earth or Mars. To learn more click on photo.

Charles Gilmore, one of the last major figures of America’s “Golden Age” of dinosaur hunting, is shown here in 1924 with a set of tail vertebrae of the dinosaur Diplodocus. The enormous job of assembling the full skeleton lay ahead, which may account for the somber expression on Gilmore’s face. Click this photo to learn more about Gilmore’s remarkable career at the Smithsonian’s National Museum of Natural History.

]]>http://smithsonianscience.org/2013/10/the-forgotten-dinosaur-hunter/feed/0Blood molecules preserved for millions of years in abdomen of fossil mosquitohttp://smithsonianscience.org/2013/10/blood-molecules-preserved-for-millions-of-years-in-abdomen-of-fossil-mosquito/
http://smithsonianscience.org/2013/10/blood-molecules-preserved-for-millions-of-years-in-abdomen-of-fossil-mosquito/#commentsMon, 14 Oct 2013 19:05:17 +0000http://smithsonianscience.org/?p=28528Sometime during the Middle Eocene a prehistoric mosquito slurped down a final blood meal then died and sank to the bottom of a pond in […]

Sometime during the Middle Eocene a prehistoric mosquito slurped down a final blood meal then died and sank to the bottom of a pond in what is now northwestern Montana. Slowly covered in fine sediments it eventually became encased and compressed in a protective layer of shale. Now, that mosquito and its blood-filled abdomen are providing scientists stunning new evidence that blood molecules can be preserved through deep time—in this case 46 million years.

Using a scanning electron microscope and mass spectrometry a team of scientists led by Dale Greenwalt of the Department of Paleobiology at the Smithsonian’s National Museum of Natural History, discovered iron and porphyrin molecules from the mosquito’s last supper very much intact inside the fossil. Porphyrin is a large planar molecule that binds iron and oxygen in the blood.

This image is a microscope photograph of a piece of shale from the Kishenehn Formation in northwestern Montana containing the fossil of a blood-engorged mosquito. Scientists from the Smithsonian and the Natural History Museum in London have discovered biomolecules from the blood in the mosquito’s abdomen that have been preserved for 46 million years.

Other members of the research team included Yulia Goreva, Sandra Siljeström and Tim Rose of the Department of Mineral Sciences at the Smithsonian’s National Museum of Natural History, and Ralph Harbach of the Department Life Sciences of the Natural History Museum, London. Their paper on the discovery appeared in the Proceedings of the National Academy of Sciences today on Monday, Oct. 14.

“This is the only known fossil of a blood engorged mosquito ever found and represents the first clear evidence that some organic molecules can be preserved in a fossil of this age,” Greenwalt explains.

To detect the molecules the team first used a scanning electron microscope equipped with an energy-dispersive X-ray spectrometer to identify various elements in the fossil. They located large amounts of iron specifically in the mosquito’s abdomen.

“Having found the iron we asked ourselves: Can we find the prophyrin molecule?” Greenwalt says. For that the team used a Time-of-Flight secondary ion mass spectrometer and “we readily found a very beautiful spectrum–a specific fingerprint–for the prophyrin molecule. The signal we obtained was very indicative of the presence of the two together—iron and prophyrin—one bound to the other in the unmistakable signature of blood.” This is the first time that this particular organic molecule has ever been definitively identified and localized in a fossil.

Smithsonian paleobiologist Dale Greenwalt holds a piece of shale from the Kishenehn Formation in northwestern Montana containing the fossil of a blood-engorged mosquito. He and his colleagues from the Smithsonian and the Natural History Museum in London discovered biomolecules from the blood in the mosquito’s abdomen that have been preserved for 46 million years. (Photo by James DiLoreto)

“We made the assumption that genetic material like DNA has not been preserved,” Greenwalt says. “We didn’t even attempt to look at it because DNA is a very liable molecule that degrades quickly.” Still, he says, this discovery opens a door to further exploration. “Without question there are probably other things contained in this fossil. We just don’t know what they might be.”

The Kishenehn Formation in northwestern Montana is unique in that it exhibits a spectacular preservation of very tiny insects like mosquitoes. Earlier this year Harbach and Greenwalt described and named two new species of mosquito—long since extinct—from this formation because their tiny body parts—wing veins, sexual organs, scales and hair-like structures on the wings—had been exquisitely preserved. Those mosquitoes were in the genus Culiseta which today feed mainly on birds, Greenwalt says. “But we have no way of knowing what the host for this blood-engorged mosquito was.”

“One of the other characteristics of insects from the Kishenehn Formation that is preserved quite often is color,” Greenwalt adds. “We have yellow insects and red insects and orange insects.”

Dale Greenwalt, left, and Tim Rose of the Department of Mineral Sciences at the Smithsonian’s National Museum of Natural History, use an energy-dispersive X-ray spectrometer to study the blood deposits in the fossil of a prehistoric mosquito. (Photo by James DiLoreto)

What conditions permit such exquisite preservation? “We don’t know but we are studying it,” Greenwalt says. The Montana climate was much warmer then—wet subtropical to tropical. “You can imagine when you think of a blood engorged mosquito, the abdomen is just blown up like a balloon and it is very fragile. If it hits water, it hits land, it hits anything, the first thing that’s going to burst would be that abdomen. Obviously the conditions that allow for such preservation are very unique and very unusual.”

“This fossilized female mosquito is an incredibly rare find,” says co-author Ralph Harbach of the Natural History Museum, London. “For it to have died immediately after feeding and be preserved without disruption to its fragile distended blood-filled belly means that we have a unique opportunity to study whether complex molecules, such as hemoglobin, can survive tens of millions of years.

“Our findings are a tantalizing glimpse into the past, not only helping us to better understand the evolution of blood-feeding in insects, but also opening up the possibility that other complex molecules, under the right conditions, might also be preserved through time.”

Known as haematophagy, blood-feeding occurs in roughly 14,000 insect species known today, including fleas and mosquitoes. Although this feeding strategy appears to have evolved independently across a variety of animals, fossil evidence of this behavior is extremely rare. This find extends the fossil record of blood-feeding to 46 million years.

]]>http://smithsonianscience.org/2013/10/blood-molecules-preserved-for-millions-of-years-in-abdomen-of-fossil-mosquito/feed/4Pieces of rare meteorite land at five different academic institutionshttp://smithsonianscience.org/2013/08/rare-meteorite-finds-home-at-five-different-academic-institutions/
http://smithsonianscience.org/2013/08/rare-meteorite-finds-home-at-five-different-academic-institutions/#commentsThu, 22 Aug 2013 13:46:37 +0000http://smithsonianscience.org/?p=28215The main mass of a rare meteorite that exploded over California’s Sierra foothills in April 2012 will be preserved for current and future scientific discoveries, […]

The main mass of a rare meteorite that exploded over California’s Sierra foothills in April 2012 will be preserved for current and future scientific discoveries, thanks to the collaborative efforts of five U.S. academic institutions.

It has found a permanent home divided among the University of California, Davis; the Smithsonian Institution’s National Museum of Natural History in Washington, D.C.; American Museum of Natural History in New York City; The Field Museum of Natural History in Chicago; and Arizona State University in Tempe. Together, the institutions have successfully acquired the biggest known portion of the Sutter’s Mill meteorite.

The main mass of the rare Sutter’s Mill meteorite before the Smithsonian Institution cut it and divided among five academic institutions: the Smithsonian Institution, American Museum of Natural History, The Field Museum of Chicago, Arizona State University and UC Davis. The 205 gram mass is the largest stone recovered from the meteorite that exploded over California’s Sierra foothills in April 2012. (Smithsonian Institution photo)

The meteorite is considered to be one of the rarest types to hit the Earth — a carbonaceous chondrite containing cosmic dust and presolar materials that helped form the planets of the solar system.

Its acquisition signifies enhanced research opportunities for each institution and ensures that future scientists can study the meteorite for years to come.

“With these museums and institutions storing the meteorite’s main mass, it leaves it in a pristine condition to preserve for future generations to study,” said UC Davis geology professor Qing-zhu Yin. “Fifty or 100 years from now, we may have new technology that will enable later generations to revisit the meteorite and do research we haven’t thought of. This gives us a better chance to realize the full scientific value of the meteorite, rather than have it be just a collector’s item.”

The meteorite formed about 4.5 billion years ago. While it fell to Earth roughly the size of a minivan before exploding as a fireball, less than 950 grams have been found. Its main mass weighs just 205 grams (less than half a pound) and is about the size of a human palm.

This X-ray CT scan of the Sutter’s Mill meteorite fall shows the cutlines for the five institutions: University of California at Davis, California (cyan 5%), Arizona State University in Tempe, Arizona (yellow 13%), the Smithsonian Institution’s National Museum of Natural History in Washington, D.C. (red 32%), American Museum of Natural History in New York City (green 34%), and The Field Museum of Natural History in Chicago (blue 16%).

The main mass was X-rayed by CT scan at the UC Davis Center for Molecular and Genomic Imaging. This was the first time a meteorite acquisition was CT scanned before its division among a consortium of institutes, allowing prior knowledge of each piece’s contents. Then it was cut into five portions, reflective of each institution’s investment, before being delivered to the institutions.

The main mass of the rare Sutter’s Mill meteorite after the Smithsonian Institution cut it and divided among five academic institutions. (Smithsonian Institution photo)

When the meteorite landed near Sutter’s Mill, the gold discovery site that sparked the California Gold Rush, it spurred a scientific gold rush of sorts, with researchers, collectors and interested citizens scouring the landscape for fragments of meteorite. The institutions that have acquired the main mass were among those that acted on this rare scientific opportunity to gain insights about the origins of life and the formation of the planets.

At UC Davis, for instance, the meteorite fell just 60 miles east of the main campus. Yin immediately traveled to the site with students and colleagues, looking for specimens and reaching out to the public to provide meteorite donations for science. He confirmed for the original discoverer of the main mass that it was carbonaceous chondrite. Yin and his UC Davis colleagues have also X-rayed the meteorite and determined its age and chemical composition.

“It just happened in our backyard,” said Yin. “I felt obligated to do something, and I still do.”

Involvement from the other institutions included:

The American Museum of Natural History worked closely with Yin to secure specimens of the Sutter’s Mill meteorite right after its fall, and performed nondestructive computed tomography (CT) scans of several specimens kindly loaned by their finders. These scans were used to determine the density of several samples to very high accuracy, confirming the type of meteorite represented by Sutter’s Mill.

The Field Museum of Natural History found several presolar stardust grains in two smaller pieces of the meteorite donated by private collector Terry Boudreaux. Presolar stardust grains are the oldest solid samples available to any lab and are essentially time capsules from before the solar system formed 4.6 billion years ago.

Arizona State University’s Meenakshi Wadhwa, director of the Center for Meteorite Studies, was contacted by Robert Haag, the private collector who owned the main mass. She then contacted the other institutions to initiate its joint acquisition.

The Smithsonian’s National Museum of Natural History prepared the meteorite for study by dividing the chondrite using high-precision thin-blade saws. The sample preparation plan was designed to maximize available material for research. The divided chondrite was then distributed to each institution for further analysis..

Last spring, UC Davis alumnus Gregory Jorgensen and donor Sandy VanderPol provided nearly 3 grams of the Sutter’s Mill meteorite to Yin’s lab at UC Davis. Those 3 grams allowed UC Davis to learn the meteorite’s age and chemical composition. The university’s recent acquisition of another 10 grams of the main mass will allow for even further research, including searching for presolar grains and performing isotopic analysis. –Source: UC Davis

]]>http://smithsonianscience.org/2013/08/rare-meteorite-finds-home-at-five-different-academic-institutions/feed/1Earth’s gold came from colliding dead starshttp://smithsonianscience.org/2013/07/earths-gold-came-from-colliding-dead-stars/
http://smithsonianscience.org/2013/07/earths-gold-came-from-colliding-dead-stars/#commentsMon, 22 Jul 2013 12:13:27 +0000http://smithsonianscience.org/?p=27771We value gold for many reasons: its beauty, its usefulness as jewelry, and its rarity. Gold is rare on Earth in part because it’s also […]

We value gold for many reasons: its beauty, its usefulness as jewelry, and its rarity. Gold is rare on Earth in part because it’s also rare in the universe. Unlike elements like carbon or iron, it cannot be created within a star. Instead, it must be born in a more cataclysmic event — like one that occurred last month known as a short gamma-ray burst (GRB).

Observations of this GRB provide evidence that it resulted from the collision of two neutron stars — the dead cores of stars that previously exploded as supernovae. Moreover, a unique glow that persisted for days at the GRB location potentially signifies the creation of substantial amounts of heavy elements — including gold.

“We estimate that the amount of gold produced and ejected during the merger of the two neutron stars may be as large as 10 Moon masses — quite a lot of bling!” says lead author Edo Berger of the Harvard-Smithsonian Center for Astrophysics (CfA).

Berger presented the finding today in a press conference at the CfA in Cambridge, Mass.

A gamma-ray burst is a flash of high-energy light (gamma rays) from an extremely energetic explosion. Most are found in the distant universe. Berger and his colleagues studied GRB 130603B which, at a distance of 3.9 billion light-years from Earth, is one of the nearest bursts seen to date.

Gamma-ray bursts come in two varieties — long and short — depending on how long the flash of gamma rays lasts. GRB 130603B, detected by NASA’s Swift satellite on June 3rd, lasted for less than two-tenths of a second.

Although the gamma rays disappeared quickly, GRB 130603B also displayed a slowly fading glow dominated by infrared light. Its brightness and behavior didn’t match a typical “afterglow,” which is created when a high-speed jet of particles slams into the surrounding environment.

Instead, the glow behaved like it came from exotic radioactive elements. The neutron-rich material ejected by colliding neutron stars can generate such elements, which then undergo radioactive decay, emitting a glow that’s dominated by infrared light — exactly what the team observed.

“We’ve been looking for a ‘smoking gun’ to link a short gamma-ray burst with a neutron star collision. The radioactive glow from GRB 130603B may be that smoking gun,” explains Wen-fai Fong, a graduate student at the CfA and a co-author of the paper.

The team calculates that about one-hundredth of a solar mass of material was ejected by the gamma-ray burst, some of which was gold. By combining the estimated gold produced by a single short GRB with the number of such explosions that have occurred over the age of the universe, all the gold in the cosmos might have come from gamma-ray bursts.

The team’s results have been submitted for publication in The Astrophysical Journal Letters and are available online at http://arxiv.org/abs/1306.3960. Berger’s co-authors are Wen-fai Fong and Ryan Chornock, both of the CfA.

]]>http://smithsonianscience.org/2013/07/earths-gold-came-from-colliding-dead-stars/feed/1Discovery: Turtle shells appeared 40 million years earlier than previously believedhttp://smithsonianscience.org/2013/05/first-turtle-shells-are-40-million-years-older-than-previously-realized/
http://smithsonianscience.org/2013/05/first-turtle-shells-are-40-million-years-older-than-previously-realized/#commentsThu, 30 May 2013 16:03:14 +0000http://smithsonianscience.org/?p=26953Unique among Earth’s creatures, turtles are the only animals to form a shell on the outside of their bodies through a fusion of modified ribs, […]

Unique among Earth’s creatures, turtles are the only animals to form a shell on the outside of their bodies through a fusion of modified ribs, vertebrae and shoulder girdle bones. The turtle shell is a unique modification, and how and when it originated has fascinated and confounded biologists for more than two centuries. A Smithsonian scientist and colleagues recently discovered that the beginnings of the turtle shell started 40 million years earlier than previously thought. The team’s research is published in the May 30 issue of Current Biology.

A living South African sideneck turtle (Pelusios niger) next to its 260 million year old relative, Eunotosaurus africanus. (Photo by Luke Norton)

The oldest known fossil turtle dated back about 210 million years, but it had an already fully formed shell, giving no clues to early shell evolution. Then a clue came in 2008 when the 220 million-year-old fossil remains of an early turtle species, Odontochelys semitestacea, were discovered in China. It had a fully developed plastron (the belly portion of a turtle’s shell), but only a partial carapace made up of distinctively broadened ribs and vertebrae on its back.

Video: Based on the work of Dr. Tyler Lyson, currently at the Smithsonian Institution, this animation shows how various fossils, particularly Eunotosaurus and Odontochelys, bridge the morphological gap between a generalized animal body plan to the highly modified body plan found in living turtles.

With this knowledge the scientists turned to newly discovered specimens of Eunotosaurus africanus, a South African species 40 million years older than O. semitestacea that also had distinctively broadened ribs. Their detailed study of Eunotosaurus indicated it uniquely shared many features only found in turtles, such as no intercostal muscles that run in between the ribs, paired belly ribs and a specialized mode of rib development, which indicates that Eunotosaurus represents one of the first species to form the evolutionary branch of turtles.

“Eunotosaurus neatly fills an approximately 30-55-million year gap in the turtle fossil record,” said Tyler Lyson, a Peter Buck Postdoctoral Fellow at the Smithsonian’s National Museum of Natural History. “There are several anatomical and developmental features that indicate Eunotosaurus is an early representative of the turtle lineage; however, its morphology is intermediate between the specialized shell found in modern turtles and primitive features found in other vertebrates. As such, Eunotosaurus helps bridge the morphological gap between turtles and other reptiles.”

The skeleton of the South African reptile, Eunotosaurus africanus, fills a gap in the early evolution of turtles and their enigmatic shell. (Photo by Tyler Lyson)

Ribs in most other animals protect internal organs and help ventilate the lungs to assist breathing. Because the ribs of turtles have been modified to form the shell, they have also had to modify the way they breathe with specialized muscles. This presents the team with their next challenge. They plan to examine the novel respiratory system in turtles and see how it evolved in conjunction with the evolution of the turtle’s shell.